[hpsdr] Beta release of linHPSDR

[John Melton]

At HAM RADIO 2018 in Friedrichshafen I gave a presentation at the HPSDR 
Academy on some new Linux software for HPSDR compatible radios called 
linHPSDR.  Please note that this is not PowerSDR running on Linux but a 
completely new Linux application.

The Beta release of this software is now available on GitHub at 
https://github.com/g0orx/linhpsdr. The README.md details the 
prerequisites and how to build the software.  It has been built and 
tested using Ubuntu 17.10 and 18.04.

The major features of the software are:

   Linux specific software
   Uses WDSP ported to Linux for the DSP library
   Supports both Protocol 1 and Protocol 2
   Supports up to 7 receivers depending on the radio
   Supports 1 transmitter
   Uses PortAudio for local audio input/output at the computer
   CAT interface over TCP/IP for each receiver
   Easy interface to WSJT-X without using a sound card or cables 
(WSJT-X.odt and .pdf) on github
   Can be interfaced to other applications using rigctl built with 
Hamlib 3.2.

Current development:

   Improved documentation (there is an early document linhpsdr-user.odt 
and .pdf) on github
   PureSignal
   Diversity
   Remote thin client

Remember this is a Beta release so there will still be some bugs in the 
code and missing features.

-- John Melton g0orx/n6lyt